Can you play an action on one base ("Base A") (e.g., Hidden Ninja Special Action "before a base scores, you may play a minion there") and thereby affect play on another base ("Base B") where there is an action-blocking card (e.g., Ornate Dome)?
Ornate Dome:
Play on a base. Destroy all other player's actions played here. Ongoing: Other players cannot play actions on this base.
An Ornate Dome on base B only prevents players from playing cards on base B (i.e. playing cards with "play on a base" on base B). I don't understand the scenario you are presenting in your question, but it doesn't seem to include anything affected by an Ornate Dome on base B. Specifically, Hidden Ninja is not played on a base, so it's not affected by Ornate Dome.
In this specific example you would not have a rules collision. Your action card would not be played on a base - it simply goes to your discard pile when used. Since it specifies that you can play a Minion, and Ornate Dome says you can't play an Action on that base you are ok.
